UP to 2,000 jobs are to be axed at Transport for London because of the credit crunch.

The transport body's 27,000 staff have been warned of a "significant reduction in jobs" over the next 18 months in an attempt to save £2.4billion and to make TfL a "leaner, fitter and more focused organisation".

The first job losses will be announced in January and most will be white-collar workers. Cut-backs are expected first in the marketing and communications, finance, business support and legal departments.

Union leaders today sought urgent talks with management and demanded to know exactly how many jobs would go. Gerry Doherty, general secretary of the TSSA transport union, which has many white-collar and managerial members, said: "This is going to be a very worrying Christmas for a great many people who won't know if they have a job next year."

He said the losses were "very bad news for Londoners who have already lost thousands of jobs in the current recession".

Although TfL stressed that "much of the job losses would come through not filling vacancies" any hint of compulsory redundancies will be met with fierce opposition from the unions.

The move follows Mayor Boris Johnson's pledge for a more cost-effective organisation after he discovered that there were more than 100 people in the press and communications section. An internal bulletin from Peter Hendy, TfL commissioner, to all staff, seen by the Evening Standard, states: "I will, with the chief officers, be making a number of changes to TfL's structure.

"While the proposed changes will result in a significant reduction in jobs within TfL these will be managed as much as possible through removal of vacant roles and transfer of existing employees into roles currently filled by non-permanent labour."

Mr Hendy said the "first stage" of the changes would begin next month and be completed by April. "It will be followed by a series of wider changes, the majority of which will take place over the next 12-18 months," adding: "This is the start of a long journey"

A senior TfL source told the Standard; "We are talking about a lot of jobs, with a figure of 2,000 being mentioned."